<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>hover</title>
    <style>
        .c1{
            display: inline-block;
            font-size: 20px;
            background-color: #30799B;
            color: orange;
        }
        .c1:hover{
            background-color: #D3E7E9;
            font-size: 30px;
            color: red;
        }
        .c2{
            height: 100px;
            width: 200px;
            border: 1px solid purple;
            color: #ff9e80;
        }
        .c2:hover{
            height: 150px;
            width: 150px;
            border: 2px dotted sandybrown;
            color: aqua;
        }
        .download{
            display: none;
        }
        .app:hover .download{
            display: block;
        }
        .app
    </style>
</head>
<body>
<div class="c1">西游记</div>
<div class="c2">红楼梦</div>
<div class="app">
    <div>点我下载</div>
    <div class="download">
        <img src="image/download.png"/>
    </div>
</div>

<div>水浒传</div>
</body>
</html>